pcmcia: remove memreq_t

Page already had to be set to 0; Offset can easily be passed as
parameter to pcmcia_map_mem_page.

CC: netdev@vger.kernel.org
CC: linux-wireless@vger.kernel.org
CC: linux-ide@vger.kernel.org
CC: linux-usb@vger.kernel.org
CC: laforge@gnumonks.org
CC: linux-mtd@lists.infradead.org
CC: linux-bluetooth@vger.kernel.org
CC: alsa-devel@alsa-project.org
CC: linux-serial@vger.kernel.org
CC: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>